Passing arrays or hashes to a subroutine would flatten their content into one long list saved in @_, sometimes this might be unwieldy so you'd need to pass these by reference instead, as is done in the prototype you mention above, this way each list would be passed and preserved as distinct unflattened member of @_.. 
my @array1=qw(something or something);
my @array2=qw(Another Something);
showElement(\@array1, \@array2);   #by reference

sub showElement{
    foreach $element (@_){
                print "Unreferenced: $element\n";
                print "Referenced:  @$element\n";
                }
    }

[download]
On the other hand, the passed lists would've been flattened into one large @_ if you pass them as follows: 
my @array4=qw(separate and yet);
my @array5=qw(flattened it);
showElements(@array4, @array5);   #as-is

sub showElements{
    foreach $element(@_){
            print "$element ";
            }
    }

[download]
You might wanna also see the "prototype" section in perlsub..

Excellence is an Endeavor of Persistence. Chance Favors a Prepared Mind.

In reply to Re: interesting prototype by biohisham
in thread interesting prototype by spx2

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.